econ.EMSep 24, 2026
SaveMulti-Dimensional Matching
Abstract
We study a matching mechanism where agents and objects are described by features rather than complete rankings. A single spectral projection reduces the problem to a one-dimensional sort, computable in O(N log N) time. We prove that on descaled features and preferences, our algorithm obtains the exact Nash Social Welfare (NSW) optimum within the projected space, with an unconditional utilitarian-welfare guarantee and a conditional NSW guarantee. The proposed mechanism is stable against exogenous noise but not strategy-proof; we provide an explicit profitable misreport. On an agentic AI shopping application, the diagnostics correctly anticipate both a success and a failure case. A 100-instance robustness study confirms the findings.
Figures & tables
| Work | Input format | Method | Truthfulness |
|---|---|---|---|
| Hylland and Zeckhauser [28] | Cardinal | Market clearing | Not guaranteed |
| Chawla et al. [12] | Multi-parameter bundles | Sequential posted pricing | Truthful-in-expectation |
| Devanur et al. [15] | Cardinal | Random assignment, config. LP | Not primary focus |
| Abebe et al. [3] | Cardinal | Random sampling | Truthful-in-expectation |
| This work | Feature prefs. , | SVD projection | Noise-stable, not strategyproof |
Table 1: Comparison to related work. Unlike prior approximate mechanisms, our truthfulness column reports what Section 4 actually proves, not an aspirational label.
| Mechanism | Mean | 95% CI half-width | Mean IR viol. (of 10) |
|---|---|---|---|
| Random | 6.52 | 5.03 | |
| Serial Dictatorship | 17.95 | 1.48 | |
| Our Method | 17.37 | 1.56 | |
| Utilitarian-Optimal | 20.01 | 1.28 |
Table 2: Figures underlying Figure 2 .